About two months ago I published a video explaining why I would be buying more shares of nitrogen fertilizer producer CVR Partners (NYSE:UAN). At the time the company just completed a turnaround and expansion that would increase its capacity by 50% and was about to announce its second quarter earnings -- the most important quarter (the growing season) for fertilizer producers. Well, things haven't worked out so well and shares have fallen 16% since my original video.

I'm not selling out of my position just yet, but the last two months have highlighted the single biggest risk facing CVR Partners and its investors and taught me an important investing lesson. In the following video, I'll explain what that is, what it means for the future of the company, and what investors can do about it.

Fool contributor Maxx Chatsko owns shares of CVR Partners, LP. Check out his personal portfolio, his CAPS page, or follow him on Twitter @BlacknGoldFool to keep up with his writing on energy, bioprocessing, and biotechnology.

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